Interior Secretary David Bernhardt told lawmakers Wednesday that he hasn’t lost sleep over rapidly rising atmospheric carbon dioxide and that he has missed some news regarding concentrations of the greenhouse gas reaching the highest mark in human history.

It was a rather stunning admission from the chief steward of America’s public lands, which are affected by wildfires, drought and other threats exacerbated by human-caused global climate change. He oversees about 500 million acres, or about one-fifth of the United States.

Researchers announced this week that atmospheric CO2 levels have exceeded 415 parts per million (ppm) for the first time in more than 3 million years, before humans walked the Earth. Rep. Matt Cartwright (D-Pa.) questioned the newly confirmed agency chief about the CO2 milestone during a hearing of the House Natural Resources Committee.

“I didn’t see that particular fact,” Bernhardt said with two demonstrators wearing green swamp monster masks seated directly behind him. Bernhardt’s revolving-door experience in lobbying and government has earned him labels such as the “ultimate D.C. swamp creature.”

“I haven’t lost any sleep over it,” the former oil and gas lobbyist said when Cartwright asked him how he would rank his level of concern about this dangerous CO2 spike.

The Trump administration’s attitude to climate change, and our country's fate, in one sentence from @SecBernhardt: "I haven't lost any sleep over it."

They don't care. Thanks to @RepCartwright, we don’t have to guess any more.

Rep. Jared Huffman (D-Calif.) also blasted Bernhardt during a testy exchange later in the hearing.

“An overwhelming consensus of the world’s climate scientists are losing sleep,” Huffman said. “It is a hair-on-fire crisis for them.”

Bernhardt responded by returning to a familiar talking point.

“The reality is that America has the No. 1 reduction in CO2 amongst developing nations,” he said. “I absolutely care that our climate is changing and that we need to factor that into our thinking. I absolutely believe that and I’ve said that over and over and over.”

Bernhardt also echoed comments he made at a congressional hearing last week, during which he blamed Congress for his own inaction to address climate change.

“If you all have a view on climate change that says don’t develop energy on federal lands, that’s fine. You have to go through a process of codifying and providing that direction,” he said Wednesday. “And if you provide it, we’ll certainly faithfully execute that.”